The present invention relates generally to emergency ejection systems for high-performance aircraft, and more particularly to an aircraft canopy that allows thru-the-canopy ejection of an ejection seat.
Modern high-speed, high-performance military aircraft are provided with emergency escape systems so that pilots and other aircrew members can quickly, and safely, exit the aircraft in case of emergency. The primary component of these systems is typically an explosively fired ejection seat. Unfortunately, most of these ejection seat systems impose a dangerous delay while the canopy is mechanically jettisoned or opened, or while a pyrotechnic charge built into the canopy transparency is fired to jettison or release part of the canopy or to burn open a hole for passage of the ejection seat.
Aircraft windshield and canopy systems are designed to meet a number of critical requirements, particularly impact protection from high energy bird strikes. Satisfying these requirements inevitably results in a transparency so tough that it must be pyrotechnically removed or severed in order to provide a clear path for ejection of an ejection seat. A transparency made of frangible material that would safely break into many small fragments when struck by the top of an ejection seat would similarly break into many small pieces when struck by a bird or airborne debris. Frangible materials can be made very strong but, almost by their very nature, cannot be made very tough.
Thus it is seen that there is a need for an aircraft canopy transparency that is both sufficiently frangible to permit an ejection seat to burst through without delay or pyrotechnics and without harm to the aircrew member, and at the same time sufficiently tough to provide adequate bird strike protection.
It is, therefore, a principal object of the present invention to provide an aircraft canopy transparency that is preferentially tough where bird strikes are likely to occur and preferentially frangible over the area where an ejection seat will exit the cockpit.
It is a feature of the present invention that it works without explosives.
It is another feature of the present invention that it does not sacrifice critical high energy bird strike protection.
It is an advantage of the present invention that it works without imposing any delay before the ejection seat can be ejected.
It is another advantage of the present invention that it does not increase the bulkiness of the canopy transparency.
It is a further advantage of the present invention that it does not materially interfere with vision through the canopy.
It is yet another advantage of the present invention that it is straightforward and low cost.
These and other objects, features and advantages of the present invention will become apparent as the description of certain representative embodiments proceeds.